The technical field of the invention relates to the control of a hybrid transmission with several modes for a motor vehicle, and more particularly, the control of such a transmission during mode change interruptions.
FIG. 1 shows a hybrid transmission for a motor vehicle comprising a primary shaft 1 connected to a flywheel 2, itself connected to an internal combustion engine 3.
A second primary shaft 6, concentric with the first primary shaft is connected to an electric machine 7.
The two primary shafts 1, 6 are provided with a set of gears 4, 8, 9 in order to transfer motive energy to a secondary shaft 10 that is also provided with a set of gears 11, 12, 14, connected to drive wheels via another intermediate drive 15 and a differential 16.
Two coupling means 5, 13 allow for different kinematic modes involving different connections of the internal combustion engine 3, the electric machine 7 and the drive wheels.
FIG. 2 illustrates the various kinematic modes available depending on the positions of the dog clutches of the coupling systems.
The first coupling means 5 between the two primary shafts 1, 6 can occupy three positions.
In a first position (position 0 of the primary dog clutch-neutral), the internal combustion engine 3 is uncoupled from the drive chain connecting the electric machine 7 to the drive wheels,
In a second position (position 2 of the primary dog clutch-road), the internal combustion engine 3 drives the drive wheels independently of the electric machine 7,
In a third position (position 1 of the primary dog clutch-coupling), the internal combustion engine 3 and the electric machine 7 are coupled so as to add their respective torques in the direction of the wheels.
The second coupling means 13 directly connecting the second primary shaft 6 connected to electric machine 7 and the secondary shaft 10 can also occupy three positions:
In a first position (position 0 of the secondary dog clutch-neutral), the electric machine 7 is not directly coupled to the secondary shaft 10.
In a second position (position 1 of the secondary dog clutch-city), the electric machine 7 is directly connected to the secondary shaft 10 with a first ratio.
In a third position (position 2 of the secondary dog clutch-highway), the electric machine 7 is directly connected to the secondary shaft 10 with a second ratio.
The three positions of each of the coupling means 5, 13 (which notably comprise dog clutches) allow new operating modes to be obtained, designated as (for example) Hyb21, ZEV1, Hyb11, Therm2, Neutral, Recharge, Hyb23, ZEV3 and Hvb33. It is possible to switch from one mode to the other by a set of transitions referenced a1 to a24 in FIGS. 2 and 3.
One of the competitive advantages of the type of transmission presented in FIG. 1 is that it does not include a mechanical synchronizer. Passing from one kinematic mode to another thus requires electronic control of the synchronization of the elements to be engaged.
This means that the passage from one kinematic mode to another must necessarily take place via a transition, during which it involves grasping the torque actuators (internal combustion engine 3 and electric machine 7) and controlling the displacement of the dog clutch(es) concerned by the transition.
Depending on the situation at hand, the mode change is more or less time-consuming. During the time it takes to make a kinematic mode change, the driver's intentions can change so as to call into question the transition in progress.
There is a need for a method for controlling a hybrid transmission capable of managing a transition interruption between kinematic modes.